The step scaling function of QCD at negative flavor number

As a computationally less costly test case for full QCD, we investigate an SU(3) Yang-Mills theory coupled to a bosonic spinor field. This theory corresponds to QCD with minus two quark flavors and is known as the bermion model. Our central object of interest is the step scaling function which describes the scale evolution of the running coupling in the Schrodinger functional scheme. We develop a suitable algorithm for the simulation of O(a) improved bermions and compare its performance with unimproved bermions and full QCD. We study in detail the lattice artefacts and the continuum extrapolation of the step scaling function from lattice simulations when improvement is used. Our results are compared to the unimproved bermion and dynamical fermion cases, and to renormalized perturbation theory in the continuum limit. We also examine the step scaling function with massive quarks in the bermion model. According to the Appelquist-Carazzone theorem the contributions from matter fields are expected to vanish for large masses, such that the step scaling function converges to the pure gauge theory case. If one wants to connect non-perturbatively different effective theories with different numbers of active quarks over flavor thresholds, lattice artefacts should be reasonably small. In order to test the feasibility of such a method, we investigate the step scaling function and its lattice artefacts for several values of the mass.Comment: 114 pages, Ph.D. thesi

Efficiencies and optimization of HMC algorithms in pure gauge theory

As a prerequisite to dynamical fermion simulations a detailed study of optimal parameters and scaling behavior is conducted for the quenched Schr\"odinger functional at fixed renormalized coupling. We compare standard hybrid overrelaxation techniques with local and global hybrid Monte Carlo. Our efficiency measure is designed to be directly relevant for the strong coupling constant as used by the ALPHA collaboration.Comment: LATTICE99 - 6 pages, 6 figures; added referenc

Schr\"odinger functional at N_f=-2

We study the Schr\"odinger functional coupling for lattice Yang-Mills theory coupled to an improved bosonic spinor field, which corresponds to QCD with minus two light flavors. This theory serves as a less costly testcase than QCD for the scaling of the coupling.Comment: Lattice2001(improvement) 3 pages, 4 figure

Schr"odinger functional at negative flavour number

The scaling of the Schr"odinger functional coupling is studied numerically and perturbatively for an SU(3) lattice gauge field coupled to an O(a) improved bosonic spinor field. This corresponds to QCD with minus two light flavours and is used as a numerically less costly test case for real QCD. A suitable algorithm is developed, and the influence of the matter fields on the continuum limit and the lattice artefacts are studied in detail.Comment: 24 pages, 7 figures, small textual change

First results on the running coupling in QCD with two massless flavours

We report on the non-perturbative computation of the running coupling of two-flavour QCD in the Schr"odinger functional scheme. The corresponding Lambda-parameter, which describes the coupling strength at high energy, is related to a low energy scale which still remains to be connected to a hadronic ``experimentally'' observable quantity. We find the non-perturbative evolution of the coupling indispensable to avoid untolerable errors in the estimated Lambda-parameter.Comment: 14 pages, 5 figures, 3 tables, some changes in the data analysis after discovery and correction of an error in Nucl. Phys. B 525, 387 (1998) by C. Christou et al. (hep-lat/9801007v2, Erratum to appear

Entwicklung der Zugangszahlen zu Werkstätten für behinderte Menschen: im Auftrag des Bundesministeriums für Arbeit und Soziales

"Der Forschungsbericht befasst sich mit den Gründen für den starken Anstieg der Zugänge zu Werkstätten für behinderte Menschen in den vergangenen Jahren. Bestandteile des Forschungsvorhabens waren eine schriftliche Befragung aller Werkstätten für behinderte Menschen zur Entwicklung der Fallzahlen in den Jahren 2001 bis 2006, die Durchführung von Fallstudien an verschiedenen Standorten, eine Darstellung von ausgewählten Beispielen guter Praxis zu Alternativen zu Werkstätten, Vermeidung von Werkstattaufnahmen und Übergängen aus Werkstätten sowie die Formulierung von Handlungsempfehlungen. Die Kernaussage der Handlungsempfehlungen lautet: Die betriebliche Integration von auf dem allgemeinen Arbeitsmarkt besonders benachteiligten Menschen muss bei den Akteuren als Leitbild stärker verankert werden, und zwar sowohl an der Schnittstelle Schule/Beruf als auch an der Schnittstelle Werkstatt/Übergang auf den allgemeinen Arbeitsmarkt." (Autorenreferat

Towards all-order Laurent expansion of generalized hypergeometric functions around rational values of parameters

We prove the following theorems: 1) The Laurent expansions in epsilon of the Gauss hypergeometric functions 2F1(I_1+a*epsilon, I_2+b*epsilon; I_3+p/q + c epsilon; z), 2F1(I_1+p/q+a*epsilon, I_2+p/q+b*epsilon; I_3+ p/q+c*epsilon;z), 2F1(I_1+p/q+a*epsilon, I_2+b*epsilon; I_3+p/q+c*epsilon;z), where I_1,I_2,I_3,p,q are arbitrary integers, a,b,c are arbitrary numbers and epsilon is an infinitesimal parameter, are expressible in terms of multiple polylogarithms of q-roots of unity with coefficients that are ratios of polynomials; 2) The Laurent expansion of the Gauss hypergeometric function 2F1(I_1+p/q+a*epsilon, I_2+b*epsilon; I_3+c*epsilon;z) is expressible in terms of multiple polylogarithms of q-roots of unity times powers of logarithm with coefficients that are ratios of polynomials; 3) The multiple inverse rational sums (see Eq. (2)) and the multiple rational sums (see Eq. (3)) are expressible in terms of multiple polylogarithms; 4) The generalized hypergeometric functions (see Eq. (4)) are expressible in terms of multiple polylogarithms with coefficients that are ratios of polynomials.Comment: 48 pages in LaTe

GEMv2 : Multilingual NLG benchmarking in a single line of code

Evaluation in machine learning is usually informed by past choices, for example which datasets or metrics to use. This standardization enables the comparison on equal footing using leaderboards, but the evaluation choices become sub-optimal as better alternatives arise. This problem is especially pertinent in natural language generation which requires ever-improving suites of datasets, metrics, and human evaluation to make definitive claims. To make following best model evaluation practices easier, we introduce GEMv2. The new version of the Generation, Evaluation, and Metrics Benchmark introduces a modular infrastructure for dataset, model, and metric developers to benefit from each others work. GEMv2 supports 40 documented datasets in 51 languages. Models for all datasets can be evaluated online and our interactive data card creation and rendering tools make it easier to add new datasets to the living benchmark.Peer reviewe

GEMv2 : Multilingual NLG benchmarking in a single line of code

Evaluation in machine learning is usually informed by past choices, for example which datasets or metrics to use. This standardization enables the comparison on equal footing using leaderboards, but the evaluation choices become sub-optimal as better alternatives arise. This problem is especially pertinent in natural language generation which requires ever-improving suites of datasets, metrics, and human evaluation to make definitive claims. To make following best model evaluation practices easier, we introduce GEMv2. The new version of the Generation, Evaluation, and Metrics Benchmark introduces a modular infrastructure for dataset, model, and metric developers to benefit from each others work. GEMv2 supports 40 documented datasets in 51 languages. Models for all datasets can be evaluated online and our interactive data card creation and rendering tools make it easier to add new datasets to the living benchmark.Peer reviewe